Question : Problem: Interrupt Time high...

What is a good threshold metric for Interrupt Time?
Would this cause a PS4 server to intermittenly stop responding?

Answer : Problem: Interrupt Time high...

First the Interrupt time sounds high. So first check for updated BIOS/Firmware/Drivers for your systems.

Second you state that the IMA Service stops.  Check the event log to see if there are any logs that point to why the IMA service stopped.  Please report back the entire Event Log information here and also search the internet/citrix site for information.  Also can you start the IMA service once its stopped or will it not start back up till a reboot?

Third, what is causing the high interrupts.  Well I don't know of a way to monitor what is causing it.  There are software and hardware interrupts.  Typically in general terms an interrupt is when software or hardware needs to "interrupt" the CPU for some task/notification.  For example a keyboard stroke is an interrupt.  Are any of your other Resource Mananger Metrics high, such as Disk Drive Context/Switches?

Fourth you state they can't connect to the DC.  How do you know this?  What information leads you to this?

Fifth, I am assuming this is one farm.  How many servers?  Are there any servers that don't exibit this behaviour and if so what are the main differences?

Sixth, has this always been an issue, or did you not have problems at one time and if so what were some main changes between those two times.